Civil Engineering and Architecture 10(7): 2943-2952, 2022 http://www.hrpub.org DOI: 10.13189/cea.2022.100713 Unit Weight, Strengths and Thermal Conductivity of Cellular Lightweight Fly Ash Geopolymer Mortar Reinforced with Polyvinyl Alcohol Sermsak Tiyasangthong 1 , Piyathida Yoosuk 1 , Kitsada Krosoongnern 1 , Bundit Krittacom 2 , Prin Nachaisit 3 , Cherdsak Suksiripattanapong 1,* 1 Infrastructure and Rail Transportation Technologies Research Unit, Department of Civil Engineering, Faculty of Engineering and Technology, Rajamangala University of Technology Isan, Nakhon Ratchasima, Thailand 2 Development in Technology of Porous Materials Research Laboratory (DiTo-Lab), Department of Mechanical Engineering, Faculty of Engineering and Technology, Rajamangala University of Technology Isan, Nakhon Ratchasima, Thailand 3 Faculty of Engineering, Rajamangala University of Technology Isan, Khon Kaen, Thailand Received July 18, 2022; Revised August 12, 2022; Accepted October 11, 2022 Cite This Paper in the Following Citation Styles (a): [1] Sermsak Tiyasangthong, Piyathida Yoosuk, Kitsada Krosoongnern, Bundit Krittacom, Prin Nachaisit, Cherdsak Suksiripattanapong , "Unit Weight, Strengths and Thermal Conductivity of Cellular Lightweight Fly Ash Geopolymer Mortar Reinforced with Polyvinyl Alcohol," Civil Engineering and Architecture, Vol. 10, No. 7, pp. 2943 - 2952, 2022. DOI: 10.13189/cea.2022.100713. (b): Sermsak Tiyasangthong, Piyathida Yoosuk, Kitsada Krosoongnern, Bundit Krittacom, Prin Nachaisit, Cherdsak Suksiripattanapong (2022). Unit Weight, Strengths and Thermal Conductivity of Cellular Lightweight Fly Ash Geopolymer Mortar Reinforced with Polyvinyl Alcohol. Civil Engineering and Architecture, 10(7), 2943 - 2952. DOI: 10.13189/cea.2022.100713. Copyright©2022 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract Lightweight materials are the most popular building wall construction materials because of their fast installation, high insulation, and low cost. However, these materials use cement as a binder. Cement production releases carbon dioxide emissions resulting in environmental issues. The research investigated the use of fly ash geopolymer and polyvinyl alcohol (PVA) to enhance the mechanical and thermal properties of cellular lightweight mortar. The effects of PVA concentrations, foam content (Fc), and curing time on properties of the cellular lightweight fly ash geopolymer (CLFAG) mortar reinforced with PVA specimens were evaluated. The results revealed that the PVA concentrations and Fc had an effect on the unit weights of the CLFAG reinforced with PVA specimens. The lowest unit weight of the specimens was 10.10 kN/m 3 at a PVA concentration of 20% and Fc of 2%. According to the Thailand industrial standard for C12 and C14 CLC block types, all mixed ingredients met the unit weight and compressive strength requirements. The correlation between unit weight and thermal conductivity of CLFAG reinforced with PVA specimens was represented by a linear function, which was a useful equation for estimating the thermal conductivity of specimens. Keywords Cellular Lightweight Concrete, Fly Ash Geopolymer, Polyvinyl Alcohol, Thermal Conductivity 1. Introduction The use of lightweight materials with low thermal conductivities in the building is continuously increasing because they can reduce the dead load of building structure [1,2] and energy consumption [3]. Many researchers have carried out properties of building walls, including cellular lightweight concrete [4], expanded polystyrene foam aggregate (EPS) concrete [5], phase change materials [6-9], and masonry units [10-14]. The cellular lightweight concrete, one of the lightweight materials, has lower unit weight and thermal conductivity than conventional materials (red brick, cement brick, and masonry unit) [15]. Borbon-Almada et al. [15]